Abstract: In order to utilize agricultural and forestry wastes and environmental protection, the PP wood-plastic composites were prepared filled with rice straw powder, rice husk powder, wood powder and bamboo powder and mixing powder with two kinds of processing methods (mixing compression molding and layers compression molding). The mechanical properties, water absorption and moisture absorption performance of the PP wood-plastic composites were investigated. The tensile sections of the composites were observed by stereo microscope. The results showed that the mechanical properties, water absorption and moisture absorption performance of the PP composites with mixing compression molding excelled that with layers compression molding, and the filler well-distributed in PP matrix and two phases had good interface combination. The PP composites filled with straw powder had good mechanical properties, and bamboo powder with PP composites had poor performance, and its mechanical properties was low, and mixing compression molding had an important role to improved water absorption and moisture absorption performance of the PP wood-plastic composites.